The present invention relates to a process for preparing optically active glycerol derivatives by a biochemical resolution which comprises (i) subjecting an ester having the general formula [(RS)-I]: ##STR4## wherein X is a halogen atom, R is an aliphatic hydrocarbon group of C.sub.1 to C.sub.8 and R' is an aromatic hydrocarbon group or an aliphatic hydrocarbon group of C.sub.1 to C.sub.2, to the action of enzymes derived from either microorganisms or animal organs, wherein said enzymes have a stereo selective esterase activity to asymmetrically hydrolyze the ester having the general formula [(R,S)-I] to give a mixture of an optically active alcohol having the general formula (II)*: ##STR5## wherein X and R' are as above and an optically active ester having the general formula (I)*: ##STR6## wherein X, R and R' are as above and (ii) obtaining the optically active alcohol having the general formula (II)* and the optically active ester having the general formula (I)* by separating operations.
The above optically active glycerol derivatives, both (R)-form and (S)-form, are very useful compounds that can be converted to various kinds of optically active drugs such as, for instance, l-carnitine, (S)-.beta.-blocker and optically active platelet activating factor antagonists.
It has been known that these optically active glycerol derivatives could be synthesized from D-mannitol (J. J. Baldwin et al., J. Org. Chem., 43, 4876 (1978)). However, this process is not suitable for an industrial scale production of the optically active glycerol derivatives since the process requires many manufacturing steps and an employment of heavy metal such as lead tetraacetate. Consequently, it has been earnestly desired to establish a simple process for preparing the optically active glycerol derivatives.
The present inventors have been studied on an asymmetrical hydrolysis of the racemic ester having the general formula [(R,S)-I] by subjecting the ester having the general formula [(R,S)-I] to the action of the enzymes having a stereo selective esterase activity in order to obtain an optically active alcohol and ester, and it was found that enzymes prepared from microorganisms of such genus as Pseudomonas, Chromobacterium, Aspergillus, Mucor or Rhizopus or enzymes prepared from animal organs could asymmetrically hydrolyze the ester having the general formula [(R,S)-I] to give the unchanged ester having the general formula ##STR7## wherein X, R and R' are as above, and the alcohol having the general formula [(S)-II]: ##STR8## wherein X and R' are as above.
The optically active ester having the general formula (I)* can be easily converted into the corresponding alcohol having the general formula (II)* by chemical hydrolysis.
The ester (I)* and alcohol (II)* can be easily obtained by separating operation such as silica-gel column-chromatography and each ester and alcohol is obtained.